This invention relates generally to apparatus and methodology for effecting medical diagnosis, and more specifically relates to systems and methodology utilizing ultrasonic techniques for such purposes.
Over the course of the last two to three decades, ultrasonic technology has played an ever-increasing role in medical diagnostics. An area of special interest for present purposes is the use of such technology for identifying and examining cardiac structures. As far back as at least 1953, Edler and Hertz described techniques wherein echoes provided by structures within the heart, could be converted into curves indicative of the movements of portions of the said structure. Techniques of this type have generally been identified under the term "echocardiography" or by the term "TM" (Time-Motion) scanning. Pursuant to these techniques, a narrow ultrasonic sound beam is projected into the regions of the heart from a surface transducer that may, e.g., be positioned as to propagate the beam between the ribs. As a pulse of ultrasonic energy is propagated inwardly through the various structures, including heart wall, valves, and the like, some of the energy is reflected back toward the transducer at the boundaries between the various structures. This reflected energy is then detected, amplified and, as desired, displayed on an oscilloscope or recorded on a strip chart.
The type of information secured by the aforementioned techniques can be of great diagnostic value since the structures being examined change in a characteristic way in certain diseases of the heart, and a skilled physician can readily determine the presence of such changes from examination of a properly obtained display or recording of the type mentioned.
Insofar as the TM scan is concerned, it may be observed that up until recently, a major problem inherent in the applicable apparatus was that the operator was, in essence, "flying blind". This is to say that the only information that such operator had regarding whether the transducer was properly oriented for the structures that he was trying to observe, was obtained by looking at the data that was being recorded on the display scope or on the recorder. Pursuant to such approach, the operator was required to tilt or angulate the transducer to cover and seek out a range of structures on which he desires to obtain recordings. Thus, the only feedback he had regarding whether the recording being made actually included the structures desired to be observed was obtained after the fact.
Recently apparatus has been reported wherein a TM scan may be obtained from a B-scan obtained from a near field array. The difficulty is that the TM scan images obtained from a near field array are not in a form familiar to diagnosticians and for such reasons are not readily correlated to the structures examined. See N. Bom, C. T. Lancee, G. Van Zwieten, F. E. Kloster and J. Roelandt, "Multi-Scan Echo Cardiography", Circulation Vol. XLVIII, November, 1973, Pages 1066-1073.
It may nextly be noted that a number of ultrasonic imaging systems have recently been reported--and in some instances, have become available for use by researchers--which systems enable a two-dimensional image, e.g., of a cardiac structure, to be generated and observed in real time. A system of this type utilizing phased array principles to steer and focus an ultrasound beam provided by an array of transducers, is described by Thurston and von Ramm in "A New Ultrasound Technique Employing Two-Dimensional Electronic Beam Steering", appearing in Acoustical Holography, Volume 5, P. S. Green, Editor, Plenum Press, 1974. Additional aspects of systems based upon such apparatus are set forth at Volume 6 of the mentioned Acoustical Holography series at page 91, in an article by von Ramm, Thurston, and Kisslo entitled "Cardiovascular Diagnosis With Real Time Ultrasound Imaging". Reference may also be usefully made to J. C. Somer, "Electronic Sector Scanning for Ultrasonic Diagnosis", appearing at page 153 of Ultrasonics for July, 1968.
The real time imaging systems above mentioned, and others as have been recently described by additional researchers, have indeed provided useful new tools for the medical diagnostician, in that, for the first time, it has become practical to directly observe an extended expanse of the heart functioning in real time, or substantially simultaneously with the functions occurrence. At the same time, however, such systems have represented but an initial approach to an extremely complex diagnostic environment. A strong desire and need on the part of the diagnostician has remained for much more flexibility, image manipulation capability, and diagnostic information then heretofore provided in the prior art. The need in particular has persisted for improved image resolution, facilities for concentrating the imaging capabilities upon specified regions within the heart or associated cardiovascular structure, and even more importantly, provision for diagnostically interrelating the usual B mode display with the other diagnostic read-outs commonly employed by cardiologists--including the well-known ECG, the phonocradiogram, and especially the already mentioned TM mode display and recording.
In accordance with the foregoing, it may be regarded as one object of the present invention, to provide a display and recording system for ultrasonic diagnosis; which system is particularly applicable to cardiology; and which is capable of directly displaying for operator investigation a high resolution and readily manipulatable real time image of cardiac structures.
It is a further object of the present invention, to provide a system of the foregoing type, which includes means for enabling simultaneous or independent display of an ECG or a phonocardiogram, and in a form which enables the system operator to readily observe such data.
It is a yet further object of the present invention, to provide a diagnostic system, wherein ultrasonic methodology is used to visualize in a fan shaped display in real time a cardiac structure or the like, thereby enabling a so-called B-mode display of such structures; which system further includes means for rapidly and automatically effecting a TM-mode read-out or scan of the portion of the cardiac structure then being displayed.
It is a still additional object of the present invention, to provide an ultrasonic imaging system particularly adapted to the generation of real time B-mode displays of cardiac structures; which system includes means for automatically securing photographs of the said B-mode display; and wherein photographing of said display may be directly correlated with a timing point referenced to an ECG being generated by the cardiac structure being observed, thereby enabling the cardiac structure to be photographically recorded at the precise point in the cardiac cycle which is deemed of interest to the diagnostician.
A still further object of the present invention, is to provide an ultrasonic diagnosing system of the aforementioned type which, in addition to including means for obtaining photographs of the real time B-mode display, includes operator-actuated means for superimposing alphanumeric and timing information upon the display, in consequence of which the resultant photographs are directly provided with precise data useful for record-keeping of other purposes, including, e.g., medico-legal or regulatory purposes.
A yet further object of the present invention, is to provide an ultrasonic diagnosing system of the aforementioned type, which in addition to including means for producing a video recording of the real time B-mode display, includes capability for superimposing precise time information on the displays being recorded, to thereby facilitate and assure accurate analysis of the recordings.